Refrigerating apparatus



Feb. 8, 1938. G. R. oHMART REFRIGERATING APPARATUS Original Filed Oct. '7, 1932 2 Sheets-Sheet l .8, 1938. G R, QHMART 2,107,644

A REFRIGERATING APPARATUS original Filed oct.- 7, .1932 2 sheets-sheet 2 ATTORNEY.

Patented Feb. s, 193s UNITED .STATES PATENTA OFFICE REFRIGERATING APPARATUS Grayston Roy Ohmart,

Detroit, Mich., assignor,

by mesne assignments, to Nash-Kelvinator Corporation, Maryland Original application 636,631. Divided Detroit,

Mich., a corporation of October A`'7, 1932, Serial No.' and this application December 12, 1935, Serial No. 54,031

1 Claim.

This invention relates to refrigerating apparatus, and more particularly to refrigerating apparatus of the compression type. Y

'I'his application is a division of my co-pending 5 application, Serial No. 636,631, led October '7,

1,932, for Refrigeratlng apparatus.

It is one of the objects of this invention to provide a. refrigerating system of the type including a compressor, a driving motor, a condenser and a refrigerant evaporator and an improved arrangement for coolingthe condenser which is espec-A ially applicable to refrigerating apparatus wherein the motor and the compressor are both entirely enclosed in a fluid-tight or hermetic'ally sealed casing.

Another Objectis to provide a fan which is .1o-'- catedrexteriorly ofthe casing-for cooling the con- `dense and to arrange for transmitting power from the motor within the improved mechanical connection without, in any way, affecting the4 huid-tightv qualities for hermetically sealing the casing enclosing themotor and the compressor.

Another object of this invention is toprovide an improved power transmitting joint for transmitting power from the interior to theexterior of a hermetically sealed casing but with a negligible amountof friction and without in any way affecting the hermetical sealing qualities of the casing. Another object of my invention is to provide intake andl discharge chambers for they compressed fluid, whichare of suiiicient size so as to evenoutthe periodic suction and discharge lto and from the cylinder so as to provide silencers which enable the operation of the compressor without pulsation hums.

c Another object of my invention is to provide an improved unloader which is arranged to by-pass refrigerant from the compression cylinder until also arranged to prevent the by-passing of refrigerantiiuid from said cylinder after the motor attains a certain speed. In practicing the' invention, a valve is used to close the by-passing'and,v

this valve is arranged so that it eijfectively closes the by-pass by mechanically operated means,

which are assisted by the pressure created within the motor attains' casing to thefan by an the motor attains a certain speed and which is (Cl. 23o- 29) ternal ydrive shaft for. connecting the motor to the Such machines, however, require compressor. the provision of a stumng box for the compressor shaft to prevent the escape of refrigerant uid from, or the admission of air into, the compressor housing. These stuiing boxes required considertirely fluid-tight. As refrigerating machines of able attention to maintain a seal which was enr-the household type have a relatively small volumetric capacity, a slight amount of leakage of refrigerant `or infiltration' of air'v'vill interfere materially with the successful operation of the machine. In addition, it has been found that stuffing boxes after they have been used over an appreciable length of timebecome noisy, which renders the apparatus entirely unsuitable for household use. Refrigerating machines of this character are generally referred to as'of the kopen type.

It has also been proposed to have the compressor and its driving motor located in a single, her- -metically sealed casing adapted to contain refrigerant fluid. With such an arrangement, the stuiling box isl entirely unnecessary as the entire operating mechanism may be conned within the interior of the casing, whereby complete fluidtightness of the refrigerating system is assured. A

Refrigeratin'g machines of this character are generally referred to as the enclosed type.

l With refrigerating machines of the open type,

a fan is usually mounted on the motor or compressorshaft for cooling the condenser. ,How-

ever. with machines ofthe enclosed type, the fan for cooling the condenser must be located on the previously been proposed to provide a separate, small motor. This necessitated the use of two motors together withstarting and control apparatus for each. Furthermore, -a motor of very small capacity is suillcient for driving the fan and such motors are relatively ineiiicient and relative- `1y unreliable as compared with the motor used for driving the compressor. In addition, if separate motors are provided and the fan motor fails to operate,l inadequate condensation of the gaseous refrigerant will result and dangerously high exteriorof the casing and, to drivethis fan, it has pressures will be produced as long as the compressor continues to operate.

In accordance with my invention, I eliminate the above objections by providing a `refrigeratir'ig machine of the type which includes "a motor and a compressor entirely enclosed within-\a hermetically sealed casing, and a fan for effecting :forced circulation of air 'over the condenser, and,

preferably, in addition, over the casing enclosing'k the motor and compressor, and have arranged for mechanically driving said fan by means of a conquired.

nection which permits power to be transmitted from the compressor motor to said fan without inY anyway aecting the hermetical sealing of the enclosing casing. By this arrangement, stufng boxes are eliminated and only :me motor is remotor 88 and compressor 40. The motorand plate 83. 'I'he opposite end of the shaft 42 is proi- .yided wim a reduced portion 45 which is iourcompressor-are operatively connected together by means of a drive shaft 42 which is journalled on one end thereof in a bearing. carried by end in a bearing 41fcarried by removable end and astator 52 carried by casting 32. The comtime as. The motor er includes a man sl, which is preferably press-fitted on the drive shaft l42.

pressor includes a cylinder body. 54, piston 55 which is adapted: to be reciprocated in a cylinder 51 bgmeans of connecting rod 58 operatively connected to the piston and an eccentric portion 8S of the drive shaft 42. A

In order to provide means for cooling the conmer, a fan 64 has been provided. Preferably,

` the fan 64 is operatedby power received from 38, which the compressor 48. A In -order to accomplish this, I have providedv a mechanical connection between'the motor 88 andthe fan 84 and'arranged such connection in sech a manner that poweris to the fan without, in any way, affecting the fluid-tight eualitiesof the hermetically The improved mechanica drive connection be- Vtween the motor 38 and fan'64coniprises, in general, wobble shaft means 18. The shaft means 18 in general, a yoke-shaped member 12 which serves to connect shaft ends 14 and 15. Between the ends vof the yoke-shaped member 12, there is a stationarypivot bearing support 11 for 'supporting the shaft means. -Also,

the ends of the yoke-shaped member 12 there is vprovided a pivotpointmember 19 which isrigidly connected to the shaft means-1l. This pivot point 19 is adapted to engage one side of the member 11 and provides a point contact therebetween. In order to maintain engagement. between the pivot point 19 and the supporting member .11, I haveprovided a second pivot point 88,' which is adapted to engage, by a point the opposite side of the snppcrting meml'ber 11. The pivot point Slis held in engagement with the bearing support" by means of a coiled spring 82, which is disposed between the plvt point member landthe shaft end 15. The spring s2, by applying its tension to the pivot point 50, tends to urge the pivot point 19 toward the bearing support 11. The bearing support i1 is carried by means of a laterally extending portion 9 formed integrally with a cover plate 92 which is clamped between an end ring 94 and tle removable end plate by means of screws .95. The shaft end ,14, pivot points 19 and 90 andthe yoke-shaped member i2 are enclosed by means of a flexible expansible bellows 91 which is sealed upon one end thereof to flange 98 on the cover- .plate 92, and the opposite end is sealed to a member |98 to which the end 15 of the shaft isscrew threaded and preferably soldered so as to provide a fluid-tight joint therebetween.

From the foregoing, it will be apparent that the casing 32 and plates 33 and H35, together with the cover plate 92 and expansible bellows 91, provide a o fluid-tight cr hermetically sealed casing which entirely encloses the motor and compressor units.

Inorder to provide a suitable mounting for the fan 54, Ihave provided a. casting E95, which is preferably carried by the end plate 35,'to which the casting |85 is secured by any 'suitable means. The castingalso provides a housing tor thefiesiblebello'ws and wobble shaft means. The fan 64 is carried by n suitable sniaiishnfi;v ini which is.

journalled a bearing |88 which is preferably preSS-tted within the casting |05. The shaft is provided with an enlarged headportion i ill in which there is provided a recess lli for receiving a sphericallyshapedend ||3 of the wobble shaft means; Within the hollow portion H6 ofthe reduced portion 45 of the drive shaft, thereis disposed a socket member I i8 provided with a recess |28 forreceiving a spherically shaped end |22 of the wobble shaft. As will be noted in Fig. 1, the

-recesses lil and 2|i are eccentricallydi'sposed with reference to the axis of ,the drive shaft and fan shaft. By this arrangement, movement of the drive shaft will'eifect orbital mcvements of the ends H3 and |22 cf the shaft means to effect rotation of the fan 64. By the presentarrangement,

it will be noted that the .pivot point 19 is held in engagement with the support member 11 by means Y of the vpivot point 80 and spring 82. Consequently, any movement of the wobble shaft will be substantially, if not entirely, free from friction,

' since there is but a-point contact. between' the shaft means and its support.

' In order to provide for lubricating movingele-l ments of the compressor and fan driving mechanism, I have provided a well |25 in the end plate 33 .for receiving, oil from the lower portion of the casing 32 by means of anoil dinger |21. Oil received in the well lows through passage |28 inte through the bore into Athe hollow portion ||6 of the reduced end of theshaft 45, whence it passes to the bearing support and pivot points. In the event a large amount of oil is-accumulated with-V in the expansible bellows, it may readily be returned .to the'interior ofthe-casina 'through passage Ill. This prevents the accumulation of a too I large a quantity of oil within the interior ofthe bellows, which would prevent proper movement of said bellows.

The fan sima 'i a1 isprovided with fabrication by means of a wick |35 formed of a bodv of nbrous material disposed within acavity |36 adjacent the shaft and bearing in easting |85. When the device is assembled, a ciiantity of oil may bedis- .posed within the casting, which is in open com munieation with the cavity through passage 89. Thus, the cil within the casting will supply lub-ricant the wick, which-in turn wilhby capillary- Y v van bore |29 in the drive shaft. Oil passes com ejup to speed before assuming the loadof the' 2,107,644 action, lubricate the shaft w1 land searing los.

refrigerant enters the compressor through an intake chamber |54, whence it passes into the cylinder under the control of a reed valve |55. The compressed refrigerant is discharged from the compression cylinder through adischarge valve mechanism |51, whence it passes into an outlet or discharge chamber |60 and through conduit |62 to the condenser. In the event any oil is returned from the evaporator to the compressor, it will, upon entering the intake chamber, descend into the4 lower portion thereof and. pass through an opening |64, which is in communication with the interior of the vcasing `30.

As will be noted in the drawings, the,intake arid discharge chambersv are considerably larger than the cross sectional interior area of the intake conduit |50 and discharge conduit |62. By providing a suction chamber of this type, it has `been found that it acts as an oil separator and which provides for automatically returning oil to the crankcase. A relatively largesuction chamber also acts as a gas surge chamber which evens out the periodic suction of the cylinder to an even flow of gas through the suction line.v By providoperation of the motor compressor unit, any suitable thermostatically controlled switch may be provided vwhich is responsive to changes of temperatures in the compartment to be cooled by the evaporator, or responsive to changes in temperature inthe evaporator. If desired, a suitable low pressure-control of the well known vtype may be provided'for controlling the operation of the motor compressor unit in accordance with changes of pressure within the vapor conduit |50.

, Preferably, the motor is of the split phase type and has a low starting torque. Under these conditions,-it has' been found desirable to provide some sort, f an unloader to allow the motor to compressor. Thus, I have provided an in'iprov'id unloader which is adapted to hold a valve member |82 away from its seat |88 until the speed of thejmotor' attains a certain value. 'By t arrangement, gas entering the compression chain ber isfbypsssed through passage |88 is attainedvby the motor and the valve member is closed by the unloader actuating mechanism.

v When the valve member is in the closed position,

any pressures created within the compression cylinder tends to maintain or to urge the' valve member towards its seat. The unloader actuating mechanism comprises a suitable sliding collar |81 carried by the drive shaft,y which is adapted to be moved by means of a ilnger |88 disposed Within a recess |89 of the collar |81. When the motor begins to operate the unloader actuating mechanism does not effect movement of the valve |82 until the'speed of said motor attains a cer.

tain value. When such a speed is attained, a pair of weights |90, which are actuated by centrifugal force against the action of springs |92, tends to move the finger |88 toward the left side` of the view in the drawings to move the -collar in that direction. When this takes place, a lever |94 is moved by the action of a spring |96 and this lever, by means of pushrod |91, tends to move the valve member downwardly .to close the valve.

When the compressor ceases operation, the slidable collar |81 is returned to the position shown in Fig. 1 of the drawings bythe action of springs |92, which overcome the action of spring |96 to slide the' collar |81 which moves lever |94 and push rod |91 to open valve |82.

From the foregoing, it will be noted that I have provided a refrigerating system of the type including a refrigerant compressor, a motor for driving the compressor, a condenser and a refrigerant evaporator and an improved arrangement for cooling the condenser, which is especially applicable to refrigerating apparatus wherein the motor and the compressor are both entirely enclosed within the fluid-tight or hermetically sealed casing. Also, it will be noted that I have provided for a fan located outside of the casing for cooling the condenser by power received from the compressor driving motor without, in any wayfaifecting the4 fluid-tight dualities of the hermetically sealed casing. In addition, I have provided f or operating the fan in such a manner so`as to minimize friotional losses.

Although only a preferred form of the invention has been illustrated, and that form described in detail, it will be apparent to those skilled in the art that various modiflcations may be made therein without departing from the spirit of the invention or from the scope of the appended claim.

I-claim: o y,

A refrigerant compressing unit comprising means providing a/compression chamber having discharge and inlet ports and a vertically extending by-pass port parallel to said chamber, a push rod adapted to be reciprocated in said by-pass port, a valve carriedby said rod with its head arranged to be acted upon by the pressure of the refrigerant in said compression chamber to Atend to urge said valve toward'its seat, a piston arranged for operation in said compression chamber, a horizontally disposed rotatable shaft operatively connected to said piston. a slidable collar carried by said shaft, linkagemechanism opf e'ratively associated 'with said push rod and co1- :lar-.Land centrifugally operatingfmeans associated 'with'said collar for controlling the movement of and linkage mechanism. GRAYSTON ROY OHMART. 

